In his book, Your Brain Is A Time Machine,
brain researcher and best-selling author Dean Buonomano uses
evolutionary biology, physics, and philosophy to present his
influential theory of how we tell, and perceive, time.

The human brain, he
argues, is a complex system that not only tells time but creates it;
it constructs our sense of chronological flow and enables "mental
time travel" - simulations of future and past events.

What is time? Is our sense of time's passage an illusion? Does
free will exist, or is the future predetermined?

In pursuing the
answers, Buonomano reveals as much about the fascinating
architecture of the human brain as he does about the intricacies
of time itself.

This virtuosic work
of popular science leads to an astonishing realization: your
brain is, at its core, a time machine.

"it seems that
everything in the universe has already happened under
eternalism.

In the context of
physics, there's two general views of the nature of time.

One we can think of
is "presentism," which only the present is real. And the second,
we can think of as "eternalism" in which the past, present,
future are equally real. And under this view, now is to time as
here is to space.

In other words, just
as I happen to be here now, it's perfectly acceptable to me that
there are other points in space I could be.

Similarly, just as I
am here now, under eternalism, there's plenty of other points in
time, the past and future, where perhaps other versions of
myself or other parts of my world line exist and are as real as
I am.

Under eternalism, the question of free will and determinism
becomes much less clear because it seems that everything in the
universe has already happened under eternalism."

Buonomano bases many of
his assumptions on the intriguing Block Universe theory according to
which time only appears to pass.

Does time only appear to pass?

The
Block Universe theory, proposed by Bradford Skow, an
associate professor of philosophy at Massachusetts Institute of
Technology (MIT) postulates that the past tense, future and
present co-exist in the Universe.

By treating the past, present, and future as materially identical,
the theory is consistent with the laws of physics as we understand
them

In one sense, the block universe theory seems unthreatening to our
intuitions:

When Skow says time
does not pass, he does not believe that nothing ever happens.

Events occur, people
age, and so on.

"Things change,"
Skow agrees, but he also believes that events do not sail
past us and vanish forever; they just exist in different
parts of spacetime.

Professor Buonomano says
it's important to have a clear understanding what free will really
means.

"I think in reality
from a neuroscience basis, what we should think of free will is
simply a subjective feeling of your unconscious brain making
decisions.

Pain might be a sense
of what happens when somebody steps on our toe.

Free will is the
subjective sense - the feeling we get when the unconscious brain
makes the decision giving us the impression that it was the
conscious mind that just made that decision," Professor
Buonomano says.

He thinks our brain was
designed to navigate our continuously changing world by predicting
what will happen and when, and by doing so he proposes a radically
new view of the brain in which the paramount function of neuronal
circuits is to generate processes whose actions define time.

He admits that physicists
and neuroscientists still have much to learn about the true nature
of time, but by exploring concepts that at first glance may seem
far-fetched, we can get a better understand of reality.

Drawing on physics, evolutionary biology and philosophy, Professor
Buonomano shows that the brain's ultimate purpose may be to predict
the future - and thus that your brain is a time machine.

It seems that
everything in the universe has already happened under eternalism.

In the context of physics, there's two general views of the
nature of time. One we can think of is "presentism," which only
the present is real. And the second, we can think of as "eternalism"
in which the past, present, future are equally real.

And under this view,
now is to time as here is to space. In other words, just as I
happen to be here now, it's perfectly acceptable to me that
there are other points in space I could be.

Similarly, just as I
am here now, under eternalism, there's plenty of other points in
time, the past and future, where perhaps other versions of
myself or other parts of my world line exist and are as real as
I am.

Under eternalism, the question of free will and determinism
becomes much less clear because it seems that everything in the
universe has already happened under eternalism.

It's called the
"Block
Universe" view in physics - in which everything has, in a
sense, a manner of speaking, already happened.

And this would mean
that what we think of as free will is, in a sense, an illusion.
But I think part of the challenge there is coming to terms of
what free will means.

I think in reality
from a neuroscience basis, what we should think of free will is
simply a subjective feeling of your unconscious brain making
decisions.

Pain might be a sense of what happens when somebody
steps on our toe.

Free will is the
subjective sense - the feeling we get when the unconscious brain
makes the decision giving us the impression that it was the
conscious mind that just made that decision.